It looks great.

However, I've used it in the past and the CSS size is _HUGE_, with no way to reduce it. We're talking about > 500KB of CSS (in my case, at least). The JavaScript is extremely bloated as well.

Honestly, being that heavy I wonder how anyone can use it. If your site is to be viewed by mobile users, adding 500KB just to style a few elements is unacceptable.

I'd much rather go with Bootstrap. It has the added benefit of having the majority of front-end devs know it, and you can buy or use a theme for free and make it look great.